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A recent study has provided clues to predator-prey dynamics in the late Pleistocene era. Researchers compared the number of tooth fractures in present-day carnivores with tooth fractures in carnivores that lived 36,000 to 10,000 years ago and that were preserved in the Rancho La Brea tar pits in Los Angeles. The breakage frequencies in the extinct species were strikingly higher than those in the present-day species.

In considering possible explanations for this finding, the researchers dismissed demographic bias because older individuals were not over represented in the fossil samples. They rejected preservational bias because a total absence of breakage in two extinct species demonstrated that the fractures were not the result of abrasion within the pits. They ruled out local bias because breakage data obtained from other Pleistocene sites were similar to the La Brea data. The explanation they consider most plausible is behavioral differences between extinct and present-day carnivores—in particular, more contact between the teeth of predators and the bones of prey due to more thorough consumption of carcasses by the extinct species. Such thorough carcass consumption implies to the researchers either that prey availability was low, at least seasonally, or that there was intense competition over kills and a high rate of carcass theft due to relatively high predator densities.

This question depends on understanding the passage as a whole. The first paragraph reports the findings of a recent study. The second paragraph examines possible explanations for the findings, ruling out all but one of them. It then suggests some inferences that researchers have drawn based on the findings and the explanation.

(A) Several explanations are entertained, but only to be dismissed; the number of tooth fractures is not presented as a well-known fact.

(B) The passage does not mention alternative methods or a debate.

(C) The likely explanation for the tooth fractures is not shown to be controversial.

(D) The passage does not question the methodology of the study.

(E) Correct. The passage explores possible explanations for a recent research finding and some tentative inferences that it might support.

The correct answer is E.

1. The primary purpose of the passage is to

(A) present several explanations for a well-known fact(B) suggest alternative methods for resolving a debate(C) argue in favor of a controversial theory(D) question the methodology used in a study(E) discuss the implications of a research finding

2. According to the passage, compared with Pleistocene carnivores in other areas, Pleistocene carnivores in the La Brea area

(A) included the same species, in approximately the same proportions(B) had a similar frequency of tooth fractures(C) populated the La Brea area more densely(D) consumed their prey more thoroughly(E) found it harder to obtain sufficient prey

3. According to the passage, the researchers believe that the high frequency of tooth breakage in carnivores found at La Brea was caused primarily by

(A) the aging process in individual carnivores(B) contact between the fossils in the pits(C) poor preservation of the fossils after they were removed from the pits(D) the impact of carnivores’ teeth against the bones of their prey(E) the impact of carnivores’ teeth against the bones of other carnivores during fights over kills

4. The researchers’ conclusion concerning the absence of demographic bias would be most seriously undermined if it were found that

(A) the older an individual carnivore is, the more likely it is to have a large number of tooth fractures(B) the average age at death of a present-day carnivore is greater than was the average age at death of a Pleistocene carnivore(C) in Pleistocene carnivore species, older individuals consumed carcasses as thoroughly as did younger individuals(D) the methods used to determine animals’ ages in fossil samples tend to misidentify many older individuals as younger individuals(E) data concerning the ages of fossil samples cannot provide reliable information about behavioral differences between extinct carnivores and present-day carnivores

5. According to the passage, if the researchers had NOT found that two extinct carnivore species were free of tooth breakage, the researchers would have concluded that

(A) the difference in breakage frequencies could have been the result of damage to the fossil remains in the La Brea pits(B) the fossils in other Pleistocene sites could have higher breakage frequencies than do the fossils in the La Brea pits(C) Pleistocene carnivore species probably behaved very similarly to one another with respect to consumption of carcasses(D) all Pleistocene carnivore species differed behaviorally from present-day carnivore species(E) predator densities during the Pleistocene era were extremely high

6. The passage suggests that tooth fractures in Pleistocene carnivores probably tended to occur less frequently

(A) during periods in which more prey were available(B) at sites distant from the La Brea area(C) in older individual carnivores(D) in species that were not preserved as fossils(E) in species that regularly stole carcasses from other species

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12 Aug 2014, 05:00

7

1

Time taken 7:30 min.1.The passage suggests that tooth fractures in Pleistocene carnivores probably tended to occur less frequentlyA. during periods in which more prey were available" more contact between the teeth of predators and the bones of prey due to more thorough consumption of carcasses by the extinct species.Such thorough carcass consumption implies to the researchers either that prey availability was low, at least seasonally, or that there was intense competition over kills and a high rate of carcass theft due to relatively high predator densities."

2.According to the passage, compared with Pleistocene carnivores in other areas, Pleistocene carnivores in the La Brea areaB. had a similar frequency of tooth fractures"hey ruled out local bias because breakage data obtained from other Pleistocene sites were similar to the La Brea data."

3.According to the passage, the researchers believe that the high frequency of tooth breakage in carnivores found at La Brea was caused primarily byD. the impact of carnivores’ teeth against the bones of their prey"more contact between the teeth of predators and the bones of prey due to more thorough consumption of carcasses"

4.The researchers’ conclusion concerning the absence of demographic bias would be most seriously undermined if it were found thatD. the methods used to determine animals’ ages in fossil samples tend to misidentify many older individuals as younger individuals"demographic bias because older individuals were not over represented in the fossil samples."

5.According to the passage, if the researchers had NOT found that two extinct carnivore species were free of tooth breakage, the researchers would have concluded thatA. the difference in breakage frequencies could have been the result of damage to the fossil remains in the La Brea pits"They rejected preservational bias because a total absence of breakage in two extinct species demonstrated that the fractures were not the result of abrasion within the pits"

6.The passage suggests that tooth fractures in Pleistocene carnivores probably tended to occur less frequentlyA during periods in which more prey were availableDuplicate of A

General Discussion

Status: On a mountain of skulls, in the castle of pain, I sit on a throne of blood.

Joined: 30 Jul 2013

Posts: 289

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Updated on: 13 Aug 2014, 20:28

2

1. A. Last paragraph implies that if the prey was scarce then the predator had more contact with the prey's bone. 2. B 5th line of the 2nd paragraph states this.3. D The last few lines of paragraph 2 points to this. The rest of the options were all dismissed by the scientists.4. D The premise of rejecting the hypothesis of not enough older samples breaks if this option were true. If the method of identifying younger from older was faulty and identified older dinos as younger, then there were clearly more older dinos among the samples under study.5. A If either or both of those samples had breakage, then it would be possible that there was some damage done by the pits that stored the fossils for all of these years.6. A Last paragraph says that prey was "seasonally available". Therefore, there were periods when prey was more available and periods when there was few or maybe none.

P.S. Question 5 has been repeated twice. The count of questions is 7 when in fact there are only 6 unique questions.

Originally posted by AmoyV on 11 Aug 2014, 16:13.
Last edited by PiyushK on 13 Aug 2014, 20:28, edited 1 time in total.

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15 Aug 2016, 06:56

5. According to the passage, if the researchers had NOT found that two extinct carnivore species were free of tooth breakage, the researchers would have concluded thatA. the difference in breakage frequencies could have been the result of damage to the fossil remains in the La Brea pitsB. the fossils in other Pleistocene sites could have higher breakage frequencies than do the fossils in the La Brea pitsC. Pleistocene carnivore species probably behaved very similarly to one another with respect to consumption of carcassesD. all Pleistocene carnivore species differed behaviorally from present-day carnivore speciesE. predator densities during the Pleistocene era were extremely high

"The explanation they consider most plausible is behavioral differences between extinct and present-day carnivores"So if the tooth -breakage problem was not there then they would have considered that Pleistocene carnivore species probably behaved very similarly to one another. I dont understand why A.

ALso The primary purpose of the passage is to

A. present several explanations for a well-known fact

E. discuss the implications of a research finding

Implication discussion is just a part of the entire passage so why not A. Because passage explore finding, then method and then implication.

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15 Aug 2016, 07:14

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abrakadabra21 wrote:

5. According to the passage, if the researchers had NOT found that two extinct carnivore species were free of tooth breakage, the researchers would have concluded thatA. the difference in breakage frequencies could have been the result of damage to the fossil remains in the La Brea pitsB. the fossils in other Pleistocene sites could have higher breakage frequencies than do the fossils in the La Brea pitsC. Pleistocene carnivore species probably behaved very similarly to one another with respect to consumption of carcassesD. all Pleistocene carnivore species differed behaviorally from present-day carnivore speciesE. predator densities during the Pleistocene era were extremely high

"The explanation they consider most plausible is behavioral differences between extinct and present-day carnivores"So if the tooth -breakage problem was not there then they would have considered that Pleistocene carnivore species probably behaved very similarly to one another. I dont understand why A.

ALso The primary purpose of the passage is to

A. present several explanations for a well-known fact

E. discuss the implications of a research finding

Implication discussion is just a part of the entire passage so why not A. Because passage explore finding, then method and then implication.

5. According to the passage, if the researchers had NOT found that two extinct carnivore species were free of tooth breakage, the researchers would have concluded thatA. the difference in breakage frequencies could have been the result of damage to the fossil remains in the La Brea pitsB. the fossils in other Pleistocene sites could have higher breakage frequencies than do the fossils in the La Brea pitsC. Pleistocene carnivore species probably behaved very similarly to one another with respect to consumption of carcassesD. all Pleistocene carnivore species differed behaviorally from present-day carnivore speciesE. predator densities during the Pleistocene era were extremely high

"The explanation they consider most plausible is behavioral differences between extinct and present-day carnivores"So if the tooth -breakage problem was not there then they would have considered that Pleistocene carnivore species probably behaved very similarly to one another. I dont understand why A.

The passage states that they rejected preservational bias because of the absence of Tooth decay. So, if they found that there was some touch decay, they could not have have proceeded further and concluded that preservational bias is the possible explanations for the finding mentioned. hence, they could not have proceeded further. Hence, A clearly states this idea.

Again, we are not sure if Pleistocene carnivore species probably behaved very similarly to one another with respect to consumption of carcasses or not. There is no information supporting this idea , hence, we cannot assume it on our own. May be they couldn't have proceeded to provide this explanation. Hence, it is a very weak answer choice.

ALso The primary purpose of the passage is to

A. present several explanations for a well-known fact

E. discuss the implications of a research finding

Implication discussion is just a part of the entire passage so why not A. Because passage explore finding, then method and then implication.

The passage states an Idea and then trying to get the possible explanation for the same. But it rejected a couple of explanations and came to a final conclusion. hence, He is providing the Only explanation for the finding. Hence, E.

A is not the right answer because the author has not provided the several explanations for the finding, rather ruled out the possible explanations and provided only One. Hence, we can say he is providing information on what the finding is implying. Hence, E._________________

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21 Aug 2016, 23:08

Interesting passage . Took 9 mins 50 seconds ,including 2 mins and 50 seconds to read -The author does not provide an opinion- He is only concerned with providing information on predator-prey dynamics- The author presents various explanations for a finding

1 .The author is concerned with the implications of the findings which is suggested in the following lines.. "Such thorough carcass consumption implies to the researchers either that prey availability was low, at least seasonally, or that there was intense competition over kills and a high rate of carcass theft due to relatively high predator densities "Hence option (E) is the right answer.

2 ."They ruled out local bias because breakage data obtained from other Pleistocene sites were similar to the La Brea data"The above excerpt suggests that both carnivores had similar breakage patterns and thereby similar frequency in tooth fractures. Hence option (B) is the right answer.

3."The explanation they consider most plausible is behavioral differences between extinct and present-day carnivores—in particular, more contact between the teeth of predators and the bones of prey due to more thorough consumption of carcasses by the extinct species."Answer D

4.the methods used to determine animals’ ages in fossil samples tend to misidentify many older individuals as younger individuals

Answer D

5."They rejected preservational bias because a total absence of breakage in two extinct species demonstrated that the fractures were not the result of abrasion within the pits."Answer A

6.Such thorough carcass consumption implies to the researchers either that prey availability was low, at least seasonally, or that there was intense competition over kills and a high rate of carcass theft due to relatively high predator densities.

Answer A
_________________

When everything seems to be going against you, remember that the airplane takes off against the wind, not with it. - Henry FordThe Moment You Think About Giving Up, Think Of The Reason Why You Held On So Long

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04 Jan 2017, 08:11

Time taken 8 minutes 20 seconds 1 wrong

4. The researchers’ conclusion concerning the absence of demographic bias would be most seriously undermined if it were found thatA. the older an individual carnivore is, the more likely it is to have a large number of tooth fracturesB. the average age at death of a present-day carnivore is greater than was the average age at death of a Pleistocene carnivoreC. in Pleistocene carnivore species, older individuals consumed carcasses as thoroughly as did younger individualsD. the methods used to determine animals’ ages in fossil samples tend to misidentify many older individuals as younger individualsE. data concerning the ages of fossil samples cannot provide reliable information about behavioral differences between extinct carnivores and present-day carnivores

Chose B got thrown off by thinking D is out of scope. Remember to read full answer choice and don't get baited/ sold on B.

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Updated on: 22 Jan 2018, 15:21

Hi Shivikaa,

Shivikaa wrote:

I got confused between D and E in Q3. Both the statements are mentioned in the paragraph. Also, in Q4, I didn't understand why we chose D as an answer. Please explain the meaning of the statement.Thanks in advance.

For Q3) This whole passage is talking about tree rings and how climatic variations affect those rings.so 1)dendrochronologists' failure to consider the prevalence of erratic weather patterns-- we are not discussing about any prevalence of erratic weather conditions here.(Wrong)2)inconsistencies introduced because of changes in methodology--We never discussed any particular methodology here(wrong)3)some tree species' tendency to deviate from the norm.(Wrong)4)the lack of detectable variation in trees with complacent rings--This is mentioned in the paragraph, but uncertainties here referring more with climatic conditions and variation in rings, this statement just tells about the variation in rings due to water supply .5)the lack of perfect correlation between the number of a tree's rings and its age---due to climatic conditions.so this is correct.see in the last line of the paragraph where author mentioned "when growth halts temporarily and then starts again." when this happens we cant really say what is tree's age.its not consistent.

Hope this is clear.

Thanks

Originally posted by skhyadi on 21 Jan 2018, 01:25.
Last edited by GMATNinjaTwo on 22 Jan 2018, 15:21, edited 1 time in total.

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24 Jan 2018, 19:18

1

Shivikaa wrote:

I got confused between D and E in Q3. Both the statements are mentioned in the paragraph. Also, in Q4, I didn't understand why we chose D as an answer. Please explain the meaning of the statement.Thanks in advance.

Quote:

3. According to the passage, the researchers believe that the high frequency of tooth breakage in carnivores found at La Brea was caused primarily by

A. the aging process in individual carnivoresB. contact between the fossils in the pitsC. poor preservation of the fossils after they were removed from the pitsD. the impact of carnivores’ teeth against the bones of their preyE. the impact of carnivores’ teeth against the bones of other carnivores during fights over kills

Refer to this portion: "The explanation they consider most plausible is behavioral differences between extinct and present-day carnivores—in particular, more contact between the teeth of predators and the bones of prey due to more thorough consumption of carcasses by the extinct species." The passage specifically talks about contact between teeth of predators and the bones OF PREY, not between teeth of predators and the bones OF OTHER CARNIVORES during fights over kills. Thus, (E) should be eliminated, and (D) is the best choice.

As for question 4, refer to this portion: "the researchers dismissed demographic bias because older individuals were not over represented in the fossil samples." We can infer that demographic bias has to do with age differences. More specifically, if all of the fossils were from OLDER individuals, then the high proportion of tooth fractures might simply be a result of the aging process . In other words, in order to accurately compare the fossil teeth to the teeth of present-day predators, we need samples representing all ages in both groups.

With that in mind, let's consider the choices:

Quote:

4. The researchers’ conclusion concerning the absence of demographic bias would be most seriously undermined if it were found that

A. the older an individual carnivore is, the more likely it is to have a large number of tooth fractures - This explains why we could have demographic bias if older individuals WERE over represented in the fossil samples. However, we are told that older individuals were NOT over represented, so (A) can be eliminated.

B. the average age at death of a present-day carnivore is greater than was the average age at death of a Pleistocene carnivore - If the OPPOSITE were true, that might hurt the author's argument by suggesting that the higher frequency of fractures among Pleistocene carnivores is a result of their longer life spans. As written, choice (B) gives us more reason to suspect that the fractures are not related to age (since the group that lived longer had fewer fractures). Regardless, the author is simply asserting that older individuals were not over represented in the fossils. Choice (B) does not affect this claim and can be eliminated.

C. in Pleistocene carnivore species, older individuals consumed carcasses as thoroughly as did younger individuals - If this were not true, it might explain why one age group would show more fractures. But choice (C) says that the two groups consumed carcasses equally thoroughly, so we don't have to worry about this possible age-related variable. Regardless, this doesn't have anything to do with the demographic bias referred to by the author. This bias only occurs if the fossils over represent certain age groups (i.e. older individuals). (C) can be eliminated.

D. the methods used to determine animals’ ages in fossil samples tend to misidentify many older individuals as younger individuals - The author claims that the fossils do not over represent older individuals. But what if the ages of the fossilized animals were not accurate? Choice (D) suggests that many of the "younger" fossilized animals may have actually been "older" individuals. In that case, the fossils WOULD over represent older individuals, and we'd have a demographic bias. Thus, choice (D) would undermine the researchers’ conclusion concerning the absence of demographic bias.

E. data concerning the ages of fossil samples cannot provide reliable information about behavioral differences between extinct carnivores and present-day carnivores - The author does not talk about using age data to determine behavioral differences. The author simply claims that the fossils do not over represent older individuals. Choice (E) is irrelevant.

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07 May 2019, 19:55

2. According to the passage, compared with Pleistocene carnivores in other areas, Pleistocene carnivores in the La Brea area

(A) included the same species, in approximately the same proportions(B) had a similar frequency of tooth fractures(C) populated the La Brea area more densely(D) consumed their prey more thoroughly(E) found it harder to obtain sufficient prey

The explanation they consider most plausible is behavioral differences between extinct and present-day carnivores—in particular, more contact between the teeth of predators and the bones of prey due to more thorough consumption of carcasses by the extinct species.Such thorough carcass consumption implies to the researchers either that prey availability was low,

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16 May 2019, 00:20

gmat1393 wrote:

2. According to the passage, compared with Pleistocene carnivores in other areas, Pleistocene carnivores in the La Brea area

(A) included the same species, in approximately the same proportions(B) had a similar frequency of tooth fractures(C) populated the La Brea area more densely(D) consumed their prey more thoroughly(E) found it harder to obtain sufficient prey

The explanation they consider most plausible is behavioral differences between extinct and present-day carnivores—in particular, more contact between the teeth of predators and the bones of prey due to more thorough consumption of carcasses by the extinct species.Such thorough carcass consumption implies to the researchers either that prey availability was low,

The piece of the passage that you've highlighted shows a difference between present day carnivores and extinct carnivores. Take another look at question #2:

Quote:

2. According to the passage, compared with Pleistocene carnivores in other areas, Pleistocene carnivores in the La Brea area

This is a different comparison than the one in your analysis -- question #2 asks us to compare Pleistocene carnivores in the La Brea area with Pleistocene carnivores in other areas. In other words, we need to compare carnivores that lived in the same time frame, but in different locations.

Here is the relevant piece of the passage to make that comparison:

Quote:

"[tooth] breakage data obtained from other Pleistocene sites were similar to the La Brea data.

This tells us that Pleistocene carnivores in multiple locations had similar tooth fractures. This aligns nicely with answer choice (B), which states that the carnivores in different locations "had a similar frequency of tooth fractures." (B) is the correct answer for question #2.

Answer choice (D) tells us that Pleistocene carnivores in the La Brea area "consumed their prey more thoroughly" than Pleistocene carnivores in other areas. Because we know from the passage that tooth breakage data were consistent across multiple locations, we cannot conclude that this is true. Eliminate (D).

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21 May 2020, 06:27

Quote:

1. The primary purpose of the passage is to

(A) present several explanations for a well-known fact(B) suggest alternative methods for resolving a debate(C) argue in favor of a controversial theory(D) question the methodology used in a study(E) discuss the implications of a research finding

Can someone quote where author is discussing the implications of research finding ?

I believe author is explaining well known fact why "The breakage frequencies in the extinct species were strikingly higher than those in the present-day species." in whole passage. Hence option A should be correct.

A recent study has provided clues to predator-prey dynamics in the lat
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29 May 2020, 03:08

Harsh2111s wrote:

Quote:

1. The primary purpose of the passage is to

(A) present several explanations for a well-known fact(B) suggest alternative methods for resolving a debate(C) argue in favor of a controversial theory(D) question the methodology used in a study(E) discuss the implications of a research finding

Can someone quote where author is discussing the implications of research finding ?

I believe author is explaining well known fact why "The breakage frequencies in the extinct species were strikingly higher than those in the present-day species." in whole passage. Hence option A should be correct.

Given the first para where the author starts with a recent finding and go onto describe that finding which is: "A recent study has provided clues to predator-prey dynamics in the late Pleistocene era. Researchers compared the number of tooth fractures in present-day carnivores with tooth fractures in carnivores that lived 36,000 to 10,000 years ago and that were preserved in the Rancho La Brea tar pits in Los Angeles. The breakage frequencies in the extinct species were strikingly higher than those in the present-day species.

In the second para, the author is gradually taking out all the biases and drawing the conclusion implied based on these findings. Also, the author intended to elaborate the findings' implication: "Such thorough carcass consumption implies to the researchers either that prey availability was low, at least seasonally, or that there was intense competition over kills and a high rate of carcass theft due to relatively high predator densities."

Hope that helps!

Kudos if helpful

gmatclubot

A recent study has provided clues to predator-prey dynamics in the lat
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